‘Some of those traits, such as fearlessness or stress immunity, can be positive. Others, such as blame externalisation or being unconcerned about the future, are more likely to be negative. One, cold-heartedness, can contribute to good and bad leadership.

‘Both great and terrible leaders score higher than the general population for psychopathic traits, but it is the mix of those traits that determines success.’

History has been littered with famous figures who exhibit psychopathic tendencies, it said, with other high-scorers including Henry VIII and Winston Churchill.